Code inspectors have taken to the streets this winter with a new weapon, palm-size computers with touch screens that snap photographs of treacherous patches of ice, snow, and slush. Thumbnail images are stamped on tickets and printed instantly with a wireless 32-ounce printer slung over an officer's shoulder like a purse.

Officials hope the immediacy of the photographs will act as a deterrent, reducing the number of slick sidewalks that twist ankles, flare tempers, and force some pedestrians to walk in the street, which can be dangerous. When property owners find a green envelope for a code violation stuffed under their doors, they are staring at evidence they will have to explain if they plan to appeal.